PRODUCTION OF LENGTH RULE PROVIDED WITH BLACK SCALE ON GOLDEN SURFACE

摘要

PURPOSE:To form an easy to see black scale on a golden surface by subjecting the surface of a length rule blank material to golden plating then coating photosensitive liquid thereon, exposing scale lines and developing the same, then peeling the golden plating of the scale lines, and further performing etching and black plating. CONSTITUTION:The entire surface of a blank material for a length rule is subjected to golden plating, and photosensitive liquid providing both an etching protecting film and a plating protecting film is coated thereon. A negative film for prescribed scale is placed on this, and is subjected to exposure treatment and further to developing. The coating film removed of the coating film in the places of the scale lines alone is heated to 250-300 deg.C in a gas furnace, whereby hard film treatment is accomplished. Next, the golden plating at the scale lines is peeled by chemical treatment, after which the exposed scale lines are etched. After black plating is carried out on the parts of the etched scale lines, the protecting film is dissolved away by a peeling agent which does not attack the black plating, whereby the length rule provided with the black scale on the golden surface is produced.